During the development of the so-called Keynesian macroeconomics, Keynes’ unemployment theory has lost much of its meaning. This process has first led to a confusion between “involuntary” and “Keynesian” unemployment; then it has put voluntary unemployment back in the debates. Through OECD reports recommendations, we show the emergence of a consensus about the nature and causes of unemployment, which can be linked to the evolution of Keynesian macroeconomics, from IS-LM to WS-PS model. More recently, the neoclassical labour supply theory has been playing an increasing role in unemployment analysis.